CVE-2026-1999
Server-Side Request Forgery in GitHub Enterprise Server Webhook Delivery Allows Access to Internal Services
Description
A Server-Side Request Forgery (SSRF) vulnerability was identified in GitHub Enterprise Server that allowed an authenticated user to access internal services bound to loopback or unspecified addresses, potentially disrupting background job processing, accessing administrative endpoints, metrics, and profiling data, or manipulating job queues. Exploitation required an authenticated user with permissions to configure webhooks (repository, organization, or GitHub App administrator privileges). This vulnerability affected all versions of GitHub Enterprise Server prior to 3.20 and was fixed in versions 3.14.22, 3.15.17, 3.16.13, 3.17.10, 3.18.4, and 3.19.1. This vulnerability was reported via the GitHub Bug Bounty program.
INFO
Published Date :
Feb. 18, 2026, 9:16 p.m.
Last Modified :
March 3, 2026, 4:16 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | HIGH | 82327ea3-741d-41e4-88f8-2cf9e791e760 | ||||
| CVSS 4.0 | HIGH | [email protected] | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update GitHub Enterprise Server to version 3.19.2 or later.
- Update GitHub Enterprise Server to version 3.18.5 or later.
- Update GitHub Enterprise Server to version 3.17.11 or later.
Public PoC/Exploit Available at Github
CVE-2026-1999 has a 2 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-1999.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-1999 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-1999
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Testing auto-merge CVE-2026-1999 variant
📡 PoC auto collect from GitHub. ⚠️ Be careful Malware.
security cve exploit poc vulnerability
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-1999 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-1999 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by [email protected]
Mar. 03, 2026
Action Type Old Value New Value Changed Description An incorrect authorization vulnerability was identified in GitHub Enterprise Server that allowed an attacker to merge their own pull request into a repository without having push access by exploiting an authorization bypass in the enable_auto_merge mutation for pull requests. This issue only affected repositories that allow forking as the attack relies on opening a pull request from an attacker-controlled fork into the target repository. Exploitation was only possible in specific scenarios. It required a clean pull request status and only applied to branches without branch protection rules enabled. This vulnerability affected GitHub Enterprise Server versions prior to 3.19.2, 3.18.5, and 3.17.11, and was fixed in versions 3.19.2, 3.18.5, and 3.17.11. This vulnerability was reported via the GitHub Bug Bounty program. A Server-Side Request Forgery (SSRF) vulnerability was identified in GitHub Enterprise Server that allowed an authenticated user to access internal services bound to loopback or unspecified addresses, potentially disrupting background job processing, accessing administrative endpoints, metrics, and profiling data, or manipulating job queues. Exploitation required an authenticated user with permissions to configure webhooks (repository, organization, or GitHub App administrator privileges). This vulnerability affected all versions of GitHub Enterprise Server prior to 3.20 and was fixed in versions 3.14.22, 3.15.17, 3.16.13, 3.17.10, 3.18.4, and 3.19.1. This vulnerability was reported via the GitHub Bug Bounty program. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Removed CVSS V4.0 AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:L/SC:L/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-918 Removed CWE CWE-863 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.14.22 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.15.17 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.16.13 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.17.10 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.18.4 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.19.1 Removed Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.17.11 Removed Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.18.5 Removed Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.19.2 Removed Reference Type https://docs.github.com/en/[email protected]/admin/release-notes#3.17.11 Types: Product, Release Notes Removed Reference Type https://docs.github.com/en/[email protected]/admin/release-notes#3.18.5 Types: Product, Release Notes Removed Reference Type https://docs.github.com/en/[email protected]/admin/release-notes#3.19.2 Types: Product, Release Notes -
Initial Analysis by [email protected]
Feb. 19, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N Added CPE Configuration OR *cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:* versions up to (excluding) 3.17.11 *cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:* versions from (including) 3.18.0 up to (excluding) 3.18.5 *cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:* versions from (including) 3.19.0 up to (excluding) 3.19.2 Added Reference Type GitHub, Inc. (Products Only): https://docs.github.com/en/[email protected]/admin/release-notes#3.17.11 Types: Product, Release Notes Added Reference Type GitHub, Inc. (Products Only): https://docs.github.com/en/[email protected]/admin/release-notes#3.18.5 Types: Product, Release Notes Added Reference Type GitHub, Inc. (Products Only): https://docs.github.com/en/[email protected]/admin/release-notes#3.19.2 Types: Product, Release Notes -
New CVE Received by [email protected]
Feb. 18, 2026
Action Type Old Value New Value Added Description An incorrect authorization vulnerability was identified in GitHub Enterprise Server that allowed an attacker to merge their own pull request into a repository without having push access by exploiting an authorization bypass in the enable_auto_merge mutation for pull requests. This issue only affected repositories that allow forking as the attack relies on opening a pull request from an attacker-controlled fork into the target repository. Exploitation was only possible in specific scenarios. It required a clean pull request status and only applied to branches without branch protection rules enabled. This vulnerability affected GitHub Enterprise Server versions prior to 3.19.2, 3.18.5, and 3.17.11, and was fixed in versions 3.19.2, 3.18.5, and 3.17.11. This vulnerability was reported via the GitHub Bug Bounty program. Added CVSS V4.0 AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:L/SC:L/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-863 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.17.11 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.18.5 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.19.2